Stoker-ram drive



D. F. GRAHAME STOKER RAM DRIVE Filed Jar 11.28. 1922 June 14, 1927.

5 Sheets-Shut l Jam 14,1927 0. F. GRAHAME STOKER RAM DRIVE Filed Jan. 28. 1922 5 Shoots-Shoot 2 June 14-, 1927. 1,632,401 D. F. GRAHAME v STOKER RAM DRIVE,

F'i led Jan. 28. 1922 5 Shoots- Shoot 3 June 14,1927. 1,632,401 D. F. GRAHAME STOKER RAM DRIVE Filed Jan. 28. 1922 5 Shoots-Shut 4 4 ll e'l/nz 'or:

Mame QM June 14,1927.

- D. F. GRAHAME STOKER HAM DRIVE Filed Jan.28. 1922 5 Sheets-Shoot 5 Patented June 14, 1927.

UlTED STATES rarer "FF-ICE.

DALLAS F. G,-O F TORONTO, ONTARIO, GANADA, ASBIGNOB, BY mama. SIGNMENTS, TO RILEY STOKEB CORPORATION, OF WORCESTER, MASSACHUSETTS,

A CORPORATION OF MASSACHUSETTS.

s'roxnn-m nnrvii.

Application filed January 28, 1922. Serial No. 583,428.

In the installation of underfeed stokers, it is sometimes desirable that the coal-feeding ram be operated by a mechanical drive, rather than a steam cylinder piston, and

5 further it is desirable that the ram of a single-unit stoker, or each ram of a multipleretort stoker'shall be operatable at intervals the periodicity of which is settable by a controlling device individual to that ram, and

310 which periodicity may, if desired, be additionally subject to modification (affecting all of the ramsof a multiple-retort furnace in common) by a suitable general regulator, responsive, for. example, to boiler-pressure conditions.

These and other desiderata I satisfy in.

the embodiment of my invention, wherein I provide for the ram, or each ram, a novel screw-drive; preferably provide for each such ram-drive an individual source of power supply such as an electric motor; and arrange for individualized motor control to afi'ord the desired individual periodicity of operation of each ram; although subject, if desired, to further control over the periodicity of ram operation, which further control may be common to all of the ram-driving devices.

Attainment of these desiderata by simple, rugged, advantageous structures, and eili-- cient coordination of the .devices are among the objects of my invention sought and attained; and other-and further objects will become apparent from the following devation of an underleed stoker drive installedin accordance with my invention; Fig. 1 is a plan view of two stoker rams and their driving motors; Fig. 2 is a longitudinal vertical section, with parts in elevation, of an individual screw-drive; Fig. 3 is a front end view thereof; Fig. 4 is a sectional detail on line 4-4 of Fig. 2, showing the pawlcarrying nut with parts thereof broken away; Fig. 5 is a section on line 55 of Fig. 4; Fig". 6 is a perspective detail of one of the pawls all said nut shown in Fig. 4; Figs; 7 and 8 are respectively plan view and end elevation of a switch structure, and Fig. 9 is by cord 21, with a suitable draft-re scription setting forth one particular em-- bodiment of my invention for purposesof hopper-equipped. ram structures (one being shown at 16 and another schematically indicated by representation of its hopper l6) forfuel. consumption under draft supplied by fan 17 for generation of steam in boiler 18 in which the pressure should, in many instances, be maintained approximately constant. which may be effected in generically-known fashion, 1 schematically indicate that the boiler 18 has steam pipe connection 19. with a damper regulator 20, the movable element of which has a movable connection,-ty ified ator, typified by weighted damper 22 in ti e fan duct. As the boiler pressure drops the damper regulator 20 pays out cord 21 to permit the damper 22-to move toward open position. Further, typically of known control of air supply accordantly with steam pressure, the fan 17 is indicated to be driven from an electric motor 23, governed as to speed by control rheostat 24 which is responsive to boiler pressure supplied through pipe 25 to a pressure-responsive rheostatactuator 25 of any suitable construction. Thus, by the means suggested, or other known organization, fan-speed will be increased and draft-controlling damper will be opened further, upon dro in the boiler For part of the regulating action,

Bit

pressure; opposite regulating action of the 1 parts following rise in the boiler pressure.

Accordantly with the stated regulation, it

is desirable that fuel supply shall be aug- It mented when boiler pressure drops and decreased when the pressure rises, and this is accommodated in the organization herein shown. Preferably, the plunger, or ram proper, 26, of each ram structure is driven by a separate electric motor, respective motors 27 and 27' for the two ram structures 16 and 16' being diagraatically shown. Each such motor has electrical switch-means for controlling its operation individually,

but these switch-means are jointly control-- regulation. To this end a rotatable part of said switch 28 is actuated by a power connection 29 from the fan shaft, to vary its speed ofrotation as the fan speed varies. Additionally, in the construction shown periodicity' of operation of the switch'28 is controllable directly from the boiler steam pressure, and to this end the. timing-switch structure 28 has a switch controlling arm 30 operatively connected with a part which is movable in response to variations in boiler pressure, such operative connection being diagrammaticallyillustrated in Fig. 1 where the arm is shown as connected through a suitable lever 32 with the cord or cable 21 so that movement of said arm 30 is controlled by the boiler-pressure responsive device 20 aforesaid. Where a plurality of motors are to be controlled, in a multiple-Stoker equipment, the power connections 29 thereof may all be driven in common from the fan 17 and the switch-controlling arms of all of the'switches (28 and 28) may be connected in common to lever 32, each such connection preferably involving a link 31 that can be disconnected. In general it isdesirable that the dwells or intervals between operations of each motor, to cause functioning of the ram plunger, may be shortened or lengthened accordantly with respective drop or rise of boiler pressure, and the connections diagrammatically illustrated, together with the me chanical construction of the time-switch hereinafter described are effective to that end.

In the specific construction shown ramplunger 26 is hollow, for reception of the operating screw, and is provided with a fixed reducing, collar 36 at itsv open, outer end.

for cooperation with the traveling nut 37 which rides on the screw-shaft 38. The hollow plunger, kept practically closed b the collar and nut, is preferably greaselled, and the screw is provided on its end with a grease-stirring blade 39' with a suitably-angle'd end 39'. The collar 36 is loosely embraced (for some axial lost-motion) between collar 40 and head 41 fixed on the body of nut 37 or made integral with it, and as the nut travels along its screw stem it will carry with it the ram-plunger. The nut structure will idl' turn in unison with the screw, rather t an travel axially along the screw and work uponthe ram plunger, whenever the nut is left free for such mauve movement, and so I make provision whereb the freedom or restraint of the nut this regard is controlled in such fashion that after completing an excursion along the screw shaft in either direction the nut will turn idly with the screw until such time as the direction of. rotation of the screw shaft is reversed, whereupon the nutwill be re strained against idle rotation and forced to make a new excursion in return-direction along the screw. Motor 27 drives the screwshaft 38 through simple belt and ulley connections 43, and the direction of screw rotation is reversed by reversal of the motor. For control of the idling action of the nut above mentioned, the nut-head 41, easily fitted into the cylinder, or body structure, of ram 16, carries a series of radially arranged gravity pawls e5,- ra'dially shiftable in notches of the head, these pawls being laterally positioned-by side rings 46'which also act as stops for the pawl-lugs .45 to limit radially-outward displacement of the pawls.

Any such pawl45, when in bottom position as shown in Fig. 4, engages in a slot 48 extending longitudinally alon the bottom of the cylinder, but at each en of the range of travel of the nut one wall of the slot 48 is beveled as at 49 or 49, these two bevels being oppositely arranged, so that when an actlve pawl reaches either end of itsrange of excursion it encounters a beveled surface across which the pawl will readily slip-(being cammed back into its recess), enabling the nut to idle, ending reversal of direction of movement of the screw shaft. The slot has, opposite its level, a squared shoulder so that, after such an idling'operation, reversal of the screw-shaft will cause the first approaching pawl to engage the squared shoulder, andthereupon the nut will start its return travel.

It will be' apparent that the screw-drive construction above characterized is importantly related to the fact of motor drive of the screw, in that the slight lost-motionafforded between collar 40 and head 41 of the screw nut as respective plunger-pushing abutments, and "the collar 36 of the plunger to be pushed thereby, insures that the motor will pick-up without substantial load, and the free rotation of the nut after completion of a working-excursion does away with the necessity for accurately timing the cessation of running of the motor. Especially this latter is important where the'actual running time of the motor is'variable, as it will be with the controlling devices herein 'illustrated. a p T e controlling switch 28 for the electric motor 27 is shown (Figs. 7:'- t o 10) as a reversing switch construction having two pairs of normally open contacts suitably connected in the circuit of the reversible motor 27 so Home 51 and 52 on a rotor 53 which is 11111 tionally operatable, step by step, from a constantly power wheel or pulley 54, the step-length t rotor will be advanced by each revolution of the power wheel beingvariable by adjustin means, of which more will be said. Such a ill justing means, however, are preferably adjustable automatically and to-this end they areshown as including the arm 305 which (as heretofore stated) is automatically movable in response to variations of steam pressure. More specifically, the insulatedly connected; pair of contactors 56 carry an inclined wear plate 55 arran ed in the ath of rotation of cam 51, so t at they wi 1 be cam-closed upon the relatively fixed pair of contact points 56 for a predetermined portion of each cycle of revo such switch .closure establishing an energized circuit for. the motor. Similarly, the dupli-' cute structure of 'contactors 57 will be sprung into engagement with the fixed oints 57 by the action of cam 52, to estab sh a reverse circuit for the motor, the cams working successively, and their arrangement preferably such that closure of switch 57- occurs rather shortly after closure of switch :56, leaving a considerable portion of a complete turn of the rotor 53 to be made before the first-acting cam 51 again comes into operation on the'nextcycle. The power wheel'54 runs loose on the rotor shaft 58, but to the latter aratchet wheel 59 is fixed, and upon'the wheel 54 is carried a pawl 60, gravity-urged toward the ratchet wheel. The pawl engages the-ratchet only when lifting pin hlnear the pawl-nose drops into-aerifpheral recess 62 of afshield ring 63 wh ch is fastened as by screws-Gite the frame 65 or" the switch. The effective length ofthe shield notch is variableby adjustment of an other notched shield-plate 70, the hub-portion-ef which, projecting through the center opening of the fixed shield-ring, is securedto and movable with a manual ad-- justing lever 71 pivoted coaxially with shaft 58. The before-mentioned lever 30 for automatic control of step length is similarly pivoted and extends alongside of lever 71 as a segmental end 30', provided with a series of notches "32 with any selected one of which a spring-latch 73 of the manual adjusting arm '5' may engage. Therefore, with lever 30' in an intermediate or neutral position, the manual adjusting arm 71 may be engaged therewith at such point as the operator selects so as to give any desired edective size of notch 62 within the allowable ran e of adjustment, but if lever 30 be automatically rough which the ution of the rotor,"

moved to one side or the other ofits initial position, the efiective size of notch 62- will accordingly be varied, lever 30 carrying manual adjusting lever 71 with it. To enable automatic adjustment to be dispensed with on occasions, lever segment 30' is provided with a spring latch 74 that may be locked in a recess 7 5 of the switch frame 65.

It will now be apparent that, with each of several rams'indivldually motor-operated, the switch for controlling each ram-driving motor may individually be set to govern thedesired periodicity of operation of the motor. If, as herein suggested, the power wheel of the motor-controlling switch be itself driven from the fan shaft or some other part the speed of which is dependent upon conditions of the furnace or of theboiler, the time taken for a complete cycle of operations of the individually adjusted switch will accordingly be varied; and fur-' thermore the pediodicity within. that variable unit of time may further be automatically varied by. the adjustment of lever 30 accordantly with conditions existing in the furnace or the boiler. Notwithstanding that, as it plainly follows, the actual length of time that the ram driving motor will work in causing an operation of the ram screw will thus be a variable quantity, the

plunger, efiected through the screw mechanism, will invariably give the motor time to pick up substantially free from load, and permit the motor to run after the ram plung er has com leted its full excursion, with the screw-nut simply idling.

While I have herein described in some detail a particular embodiment of my invention it will be apparent to those skilled in the art that in many respects my invention, under the appended claims, is not limited to the specific details of structure and arrange ment that are shown in the drawings for illustrative purposes, and that in manyspecific features of novelty and advantage my invention may be embodied in forms w1dely differing in detail from those herein illustratively shown.

I claim:

1. The combination with an underfeed stoker having a plurality of rams, a boiler,

connections between the motor and the ramrespective ram-plunger driving screws, an electric motor for each said screw, arranged to actuate it, a circuit control switch for each said motor, arranged to start and stop it, and means whereby said pressure-responsive device controls the periodicity of such operation of said motor switches thereby to vary the duration of dwells between ram-plunger reciprocations.

3. The combination with an underfeed stoker having a plurality of rams, a boiler,.

J stoker having a plurality of rams, .a boiler,

' crating said mechanisms, and means con-- and a boiler-pressure responsive device, of respective ram-plunger driving screws, an electric motor for each thereof, a circuit control switch mechanism for each motor including means settable to determine periodicity of the motors operation, means for optrolled by said pressed responsive device for varying the setting of said switch parts.

'5. The combination with an underfeed stoker having a plurality of rams, of respective ram-plunger driving means, an electric motor for eacli thereof, a circuit control switch mechanism for each motor individually settable to determine periodicity of said motors o eration, and means for operating said mec anisms.

6. The combination with an' underfeed.

stoker having a plurality of rams, a boiler. and a boiler-pressure responsive device, of

'respective rain-plunger driving means, an

electric motor for each thereof, a circuit control switch mechanism for each motor individually setta-ble to determine periodicity of each motors operation, and means for operating said mechanisms controlled by said boiler-pressure responsive device to vary the time of a cycle of operations of said switches.

7. The combination of a boiler, an underfeed stoker therefor having a ram-plunger, a boiler-pressure responsive device, a motorcontrolling switch, means controlled by said responsive device to control said switch, an electric motor connected with said switch to be started and stopped thereby, a screw driven by the motor, and means for connecting said screw and the ram plunger to drive the latter in either direction, said means arranged to idle during continued rotation of the screw after screw-impelled movement of the plunger to an end of a definite travelrange. V

8. The combination of a boiler, an underfeed stroker therefor having a pluralitypf ram-plungers, a boilerressure responsive device, and a plurality 0 sets of controlling instrumentalities, each respectively for one of said ram-plungers, each comprising a motor circuit controlling switch operatively connected with said pressure-responsive device for control thereby, an electric motor connected with said switch to be started and stopped thereby, a screw driven by the motor, and means-for connecting said screw and the ramplimger to drive the latter in either direction, -said means arranged to idle during continued-rotation of the screw after screw-impelled movement of the plunger to either end of a definite travel-range.

9. The combination of a boiler, a steampressure responsive devic'eio eratively associated therewith, an under eed stoker for said boiler having tric motor operatively connected with said ram-plunger to actuate it, a circuit-controlling switch for said motor to start and stop the same, and means normallyjoperatingpe f riodically to actuate said circuit-contra switch to occasion dwells between operations a ram-plunger, an elec-,

of said plungerby stoppage of the motor,

said means being operatively connected with said pressure responsive device to be controlled thereby for variation of the periodic-' ity of operation of said switch.

10.- The combination with an underfeed stoker having a feed-ram and a steam boiler,

of an electric motor operatively connected ,with said ram to drive it, a circuit-controlsaid ram-plunger to drive-the latter in recipocatiori as the direction of operation of the'electric motor is reversed, a switch mechanism including electric switch means in the circuit for said motor and adapted and arranged to start, stop and reverse said motor, means to drive said switch mechanism in cyclic operation, and means controlled by said pressure-responsive device controlling the periodicity of said cyclic operations of the switch mechanism.

12. The combination of a boiler, an underfeed stoker therefor having a ram-plunger, a steam-pressure responsive device operatively associated with the boiler, a reversible electric motor operatively connected with said ram-plunger to drive it inreciprocation, reversing the reciprocative direction as the direction of operation of the motor is reversed, a timing-switch mechanism including electric switch means in the circuit for said motor and adapted and arranged to start, stop and reverse said motor, means to drive such switch mechanism in cyclic operation, means controlled by said pressureresponsive device controlling the periodicity of said cyclic operation of said switch mechanism, and additional means, manually set- 10 table, for varying the periodicity of said cyclic operations.

DALLAS F. GRAHAME. 

